From patchwork Thu Jun 11 15:57:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Salyzyn X-Patchwork-Id: 224571 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EC1CBC433DF for ; Thu, 11 Jun 2020 15:58:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C0112206A4 for ; Thu, 11 Jun 2020 15:58:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=android.com header.i=@android.com header.b="Dwcsd4m+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728526AbgFKP6R (ORCPT ); Thu, 11 Jun 2020 11:58:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45524 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728258AbgFKP6Q (ORCPT ); Thu, 11 Jun 2020 11:58:16 -0400 Received: from mail-pj1-x1042.google.com (mail-pj1-x1042.google.com [IPv6:2607:f8b0:4864:20::1042]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C5882C08C5C1 for ; Thu, 11 Jun 2020 08:58:16 -0700 (PDT) Received: by mail-pj1-x1042.google.com with SMTP id a45so3228462pje.1 for ; Thu, 11 Jun 2020 08:58:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=android.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=wmMY+MRX2wFNr8xH7Gjjy3WCjLNZOMBrX6oRooxRsyg=; b=Dwcsd4m+00R3mg5s04yD789hqMz8Z/ZYf9KeIlCkPSk9rHdho67fUWC8GIhjHTBy4C Wf1SHNNcuvtEIX37QR7LEo5o0MTkclIw9YH+b79ZOxR493utSFR6IYIQ5zAN9Yba7Cb9 hZCHhddcMqE6/kitQAqNxfiG/hHhGKyf5tsU29c0LCt8hTI7SSRdr32abFjFtnZCj4J7 TNpLymm7x52Uf+rbQEKxkCptyWyuQYkC2m/naag126EfUztdUFclB/pwMijOQZWYv5aW SnuBeoomtckzp01yaljaHr6QXk+osmmtek9IcrDrV5sF/k99EiAngMrkSuxrh82H3BUf UfBg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=wmMY+MRX2wFNr8xH7Gjjy3WCjLNZOMBrX6oRooxRsyg=; b=pCtEh5XZ1OltiiNU6iGD+jwe2ADQJqcoALSMj4xtG9hZsnEHN4cgRlZQhAqRhidxGf 07OBO2LjfzrL8sOYHQ/B2H/I8uuFwm3jS29VOOOID4ke6Si+aS3BKhHoO/sXkqwyP8gW 9KSjhTXZB6A27uZsPoSEToPB8rT2frlnBm28MHRdyR7kPkeIe4upgaPr/6ILlOnHn/RG 5z87EaRF46uUqWqiHtSU37DXlafCiZVBcH2ZgNZwP/1U73gkI9si96xC5dL8vREn3VL+ mkaYJ5N0nhWhFhfZo33ELn9nha5WDJChvQTeMUNUk6lbnDYHyy6pM0kNuzjQAPmd74Bx Y6+Q== X-Gm-Message-State: AOAM532+C7SThAyU9SwazfvP09J12PLNM2hme+A7f6qdQdMcaj2EDnuN vXnlCtBfcoa/IT7ueuzLX2AnMQ== X-Google-Smtp-Source: ABdhPJx135n/L8uDgvZxsYAMgqqYKHRKnMrr+Pc6mDxL6NpxQa4sy25j9Jeu9J8cgQ6IAhO+DfyVqg== X-Received: by 2002:a17:90a:e288:: with SMTP id d8mr9137569pjz.173.1591891096359; Thu, 11 Jun 2020 08:58:16 -0700 (PDT) Received: from nebulus.mtv.corp.google.com ([2620:15c:211:200:5404:91ba:59dc:9400]) by smtp.gmail.com with ESMTPSA id i67sm3489801pfb.82.2020.06.11.08.58.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 11 Jun 2020 08:58:15 -0700 (PDT) From: Mark Salyzyn To: linux-kernel@vger.kernel.org Cc: kernel-team@android.com, Chiawei Wang , Mark Salyzyn , stable@vger.kernel.org, Andy Lutomirski , Thomas Gleixner , Vincenzo Frascino Subject: [PATCH] lib/vdso: use CLOCK_REALTIME_COARSE for time() Date: Thu, 11 Jun 2020 08:57:50 -0700 Message-Id: <20200611155804.65204-1-salyzyn@android.com> X-Mailer: git-send-email 2.27.0.278.ge193c7cf3a9-goog MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Chiawei Wang CLOCK_REALTIME in vdso data won't be updated if __arch_use_vsyscall() returns false. It will let time() return an incorrect time value. Since time() is designed to return the seconds since the Epoch, using CLOCK_REALTIME_COARSE can still fulfill the request and never fails. Signed-off-by: Chiawei Wang Signed-off-by: Mark Salyzyn Cc: linux-kernel@vger.kernel.org Cc: kernel-team@android.com Cc: stable@vger.kernel.org # 5.4+ --- lib/vdso/gettimeofday.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c index a2909af4b924..7ea22096cbe2 100644 --- a/lib/vdso/gettimeofday.c +++ b/lib/vdso/gettimeofday.c @@ -324,7 +324,7 @@ __cvdso_time_data(const struct vdso_data *vd, __kernel_old_time_t *time) vd->clock_mode == VDSO_CLOCKMODE_TIMENS) vd = __arch_get_timens_vdso_data(); - t = READ_ONCE(vd[CS_HRES_COARSE].basetime[CLOCK_REALTIME].sec); + t = READ_ONCE(vd[CS_HRES_COARSE].basetime[CLOCK_REALTIME_COARSE].sec); if (time) *time = t;